Treasury Bonds
Every public country opens its bond programme with a first emission of 10,000 treasury bonds — private countries have no parliament to vote a loan, so they never issue any. Every bond in the world is worth the same: a face value of $0.10, paid in the issuer's own national currency at the exchange rate of the day the emission opened — so the price differs from country to country but the value never does. Each emission is a separate tranche with its own daily coupon rate and its own maturity date, so two bonds from the same country can pay differently and redeem on different days. Hold a bond and the state budget pays its emission's coupon every single day; when the emission matures the treasury buys it back at face value. Buy straight from the treasury or from other citizens, then hold for the coupon or list your own at any price you like. A country's credit rating climbs and falls with its budget — and if the treasury can no longer cover its coupons, it defaults on its debt until its finances recover.
Mexico
This treasury could not cover its coupon and has defaulted. Bond payments are suspended until the budget recovers above 100.
